# CVE-2026-97561: smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid

> An untrusted SMB server can override local file ownership settings, bypassing forceuid/forcegid mount options and potentially leading to privilege escalation.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104867, BELL-CVE-2026-97561, DEBIAN-CVE-2026-97561, GHSA-vg8h-339p-69c7, UBUNTU-CVE-2026-97561

## What is CVE-2026-97561?

CVE-2026-97561 is a vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid

When the administrator mounts with forceuid or forcegid (uid=/gid=
mount options), they expect all files to appear owned by the specified
user/group.  However, several code paths unconditionally called
sid_to_id() to overwrite cf_uid/cf_gid with server-provided values,
ignoring the administrator's explicit override:

  - smb311_posix_info_to_fattr() (stat via POSIX extensions)
  - cifs_posix_to_fattr() (readdir via POSIX extensions)
  - parse_sec_desc() (CIFS ACL ownership mapping)

This allowed an untrusted server to dictate local file ownership even
when the mount was configured to force specific uid/gid values.

Fix all three call sites to check CIFS_MOUNT_OVERR_UID and
CIFS_MOUNT_OVERR_GID before calling sid_to_id(), following the
same pattern already used by cifs_unix_basic_to_fattr() for unix
extensions.

## Which versions are affected by CVE-2026-97561?


## How do I fix CVE-2026-97561?

Apply the vendor's patch.

## Is CVE-2026-97561 being exploited?

There is no known exploitation of CVE-2026-97561 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97561 and fix it if it is affected.

What it is: CVE-2026-97561 is a vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-97561 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-97561/ (Markdown: https://insights.sbomify.com/CVE-2026-97561/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97561
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97561
- OSV: https://osv.dev/vulnerability/CVE-2026-97561

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97561/
Summaries are generated and may contain mistakes; the official description above is the record.